Hepatocellular Carcinoma: Does the Background Liver With or Without Cirrhosis Matter?

OBJECTIVES

The pathologic differences between hepatocellular carcinoma (HCC) arising in noncirrhotic and cirrhotic livers have not been well studied.

METHODS

We performed a retrospective analysis of 378 HCC cases (95 in noncirrhotic, 283 in cirrhotic livers) from pathology archives (2010-2017).

RESULTS

Patients without cirrhosis were more likely to have hepatitis B (13.68% vs 2.83%, P < .001) or no known liver disease (30.53% vs 4.24%, P < .001), while hepatitis C was more common in patients with cirrhosis (65.72% vs 30.53%, P < .001). HCCs in noncirrhotic livers were larger in size (P < .001); were more likely to have a macrotrabecular histologic pattern (13.68% vs 4.95%, P < .01); were more likely to have fibrolamellar (3.16% vs 0%, P = .02), macrotrabecular-massive (13.68% vs 6.01%, P = .03), and clear cell (16.84% vs 6.71%, P < .01) subtypes; have a higher histologic grade (P < .01); be anaplastic tumor cells (P < .001); have a higher rate of vascular invasion (P < .01); and have a higher tumor stage (P = .04).

CONCLUSIONS

The findings indicate that HCCs in noncirrhotic livers demonstrate a larger tumor size; have a more macrotrabecular histologic pattern; have fibrolamellar, macrotrabecular-massive, and clear cell subtypes; have a higher tumor grade and stage; have a higher rate of vascular invasion; and have more anaplastic tumor cells compared with cirrhotic livers. Further studies to explore different pathways that promote oncogenesis in noncirrhotic livers are needed to better understand the pathogenesis of HCC.

THU0154 PERCEPTIONS ABOUT INTERVENTIONS TO ENHANCE INFLUENZA VACCINE UPTAKE DIFFER BETWEEN VACCINATED AND UNVACCINATED RA/JIA PATIENTS

Background:

To optimize the control of vaccine preventable diseases, high immunization coverage rates must be achieved. Influenza vaccination rates among patients with rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) are suboptimal. Understanding patient preferences for interventions that may increase vaccine uptake is the first step to inform the development of specific strategies to enhance vaccine coverage in RA/JIA.

Objectives:

To compare the perceptions of vaccinated and unvaccinated RA/JIA patients on a multi-modal intervention to enhance seasonal influenza vaccine coverage.

Methods:

During the 2018-2019 influenza season, a multi-modal intervention was implemented at a large Canadian academic center. This consisted of (i) a letter sent from the Division of Rheumatology to patients addressing common misconceptions about flu vaccines and encouraging patients to plan for immunization; (ii) a nurse providing inactivated influenza vaccine at the rheumatology clinics for the first 7 weeks after the vaccine was released, and (iii) clinics posters specifically designed for rheumatic patients and rheumatologists to prompt a discussion on influenza prevention. Patients that were vaccinated on site completed a survey evaluating the relevance of the individual components of the intervention. After the intervention, during a scheduled rheumatology visit, RA/JIA patients were asked to complete a similar survey. We compared the responses from RA/JIA patients that were vaccinated at our institution, to those of patients that reported not having received the influenza vaccine in 2018-2019.

Results:

During the intervention, 116 immunized RA/JIA patients completed the first survey. Forty RA/JIA patients not vaccinated during the 2018-2019 season completed the post-intervention survey. Both vaccinated and unvaccinated groups were mostly female (74.1% versus 87.2%), but vaccinated patients were older (50.8±19.4 versus: 40.5±14.9; 95% CI 3.7%,17%), and had shorter disease duration (10.1±9.3 versus 15.0±9.8; 95% CI -8.9%,-1.1%) than those not vaccinated. Unvaccinated patients were less likely than vaccinated patients to approve of the clinic’s provision of influenza vaccine (98.2% versus 75%; 95% CI 12.8%, 43.5%). When asked about elements of the intervention, unvaccinated patients were less likely than vaccinated patients to consider posters (65.2% versus 38.9%; 95% CI 7.9%, 42.9%), letters (69.4% versus 35.3%; 95% CI 16.2%, 51.2%), or phone calls (58.0% versus 41.7%; 95% CI 2.1%, 33.5%) as good reminders.

Conclusion:

Unvaccinated RA/JIA patients’ opinions about interventions to increase vaccine uptake differ from vaccinated patients. Alternative, novel strategies to target vaccine hesitant RA/JIA patients are needed to optimize vaccine coverage.

Disclosure of Interests:

None declared

Are older drivers' driving patterns during an on-road driving task representative of their real-world driving patterns?

OBJECTIVE

The current study investigated whether older drivers' driving patterns during a customized on-road driving task were representative of their real-world driving patterns.

METHODS

Two hundred and eight participants (male: 68.80%; mean age = 81.52 years, SD = 3.37 years, range = 76.00-96.00 years) completed a customized on-road driving task that commenced from their home and was conducted in their own vehicle. Participants' real-world driving patterns for the preceding 4-month period were also collected via an in-car recording device (ICRD) that was installed in each participant's vehicle.

RESULTS

During the 4-month period prior to completing the on-road driving task, participants' median real-world driving trip distance was 2.66 km (interquartile range [IQR] = 1.14-5.79 km) and their median on-road driving task trip distance was 4.41 km (IQR = 2.83-6.35 km). Most participants' on-road driving task trip distances were classified as representative of their real-world driving trip distances (95.2%, n = 198).

CONCLUSIONS

These findings suggest that most older drivers were able to devise a driving route that was representative of their real-world driving trip distance. Future research will examine whether additional aspects of the on-road driving task (e.g., average speed, proportion of trips in different speed zones) are representative of participants' real-world driving patterns.

Development and evaluation of a driving observation schedule (DOS) to study everyday driving performance of older drivers

This paper describes the development and evaluation of an on-road procedure, the Driving Observation Schedule (DOS), for monitoring individual driving behavior. DOS was developed for use in the Candrive/Ozcandrive five-year prospective study of older drivers. Key features included observations in drivers' own vehicles, in familiar environments chosen by the driver, with start/end points at their own homes. Participants were 33 drivers aged 75+ years, who drove their selected route with observations recorded during intersection negotiation, lane-changing, merging, low speed maneuvers and maneuver-free driving. Driving behaviors were scored by a specialist occupational therapy driving assessor and another trained observer. Drivers also completed a post-drive survey about the acceptability of DOS. Vehicle position, speed, distance and specific roadways traveled were recorded by an in-vehicle device installed in the participant's vehicle; this device was also used to monitor participants' driving over several months, allowing comparison of DOS trips with their everyday driving. Inter-rater reliability and DOS feasibility, acceptability and ecological validity are reported here. On average, drivers completed the DOS trip in 30.48min (SD=7.99). Inter-rater reliability measures indicated strong agreement between the trained and the expert observers: intra-class correlations (ICC)=0.905, CI 95% 0.747-0.965, p<0.0001; Pearson product correlation, r (18)=.83, p<0.05. Standard error of the measurement (SEM), method error (ME) and coefficient of variation (CV) measures were consistently small (3.0, 2.9 & 3.3%, respectively). Most participants reported being 'completely at ease' (82%) with the driving task and 'highly familiar with the route' (97%). Vehicle data showed that DOS trips were similar to participants' everyday driving trips in roads used, roadway speed limits, drivers' average speed and speed limit compliance. In summary, preliminary findings suggest that DOS can be scored reliably, is of feasible duration, is acceptable to drivers and representative of everyday driving. Pending further research with a larger sample and other observers, DOS holds promise as a means of quantifying and monitoring changes in older drivers' performance in environments typical of their everyday driving.

A question prompt list for patients with advanced cancer in the final year of life: development and cross-cultural evaluation

BACKGROUND

Clinicians and patients find prognosis and end-of-life care discussions challenging. Misunderstanding one's prognosis can contribute to poor decision-making and end-of-life quality of life. A question prompt list (booklet of questions patients can ask clinicians) targeting these issues may help overcome communication barriers. None exists for end-of-life discussions outside the palliative care setting.

AIM

To develop/pilot a question prompt list facilitating discussion/planning of end-of-life care for oncology patients with advanced cancer from Australia and the United States and to explore acceptability, perceived benefits/challenges of using the question prompt list, suggestions for improvements and the necessity of country-specific adaptations.

DESIGN

An expert panel developed a question prompt list targeting prognosis and end-of-life issues. Australian/US semi-structured interviews and one focus group elicited feedback about the question prompt list. Transcribed data were analysed using qualitative methods.

SETTING/PARTICIPANTS

Thirty-four patients with advanced cancer (15 Australian/19 US) and 13 health professionals treating such patients (7 Australian/6 US) from two Australian and one US cancer centre participated.

RESULTS

Most endorsed the entire question prompt list, though a minority queried the utility/appropriateness of some questions. Analysis identified four global themes: (1) reinforcement of known benefits of question prompt lists, (2) appraisal of content and suggestions for further developments, (3) perceived benefits and challenges in using the question prompt list and (4) contrasts in Australian/US feedback. These contrasts necessitated distinct Australian/US final versions of the question prompt list.

CONCLUSIONS

Participants endorsed the question prompt list as acceptable and useful. Feedback resulted in two distinct versions of the question prompt list, accommodating differences between Australian and US approaches to end-of-life discussions, highlighting the appropriateness of tailoring communication aides to individual populations.

Patient perspectives regarding communication about prognosis and end-of-life issues: how can it be optimised?

OBJECTIVE

To explore patients' perspectives across two cultures (Australia and USA) regarding communication about prognosis and end-of-life care issues and to consider the ways in which these discussions can be optimised.

METHODS

Fifteen Australian and 11 US patients completed individual semi-structured qualitative interviews. A further 8 US patients participated in a focus group. Interviews and focus group recordings were transcribed verbatim and interpreted using thematic text analysis with an inductive, data-driven approach.

RESULTS

Global themes identified included readiness for and outcomes of discussions of prognosis and end-of-life issues. Contributing to readiness were sub themes including patients' adjustment to and acceptance of their condition (together with seven factors promoting this), doctor and patient communication skills, mutual understandings and therapeutic relationship elements. Outcomes included sub themes of achievement of control and ability to move on. A model of the relationships between these factors, emergent cross cultural differences, and how factors may help to optimise these discussions are presented.

CONCLUSION

Identified optimising factors illustrate Australian and US patients' perspectives regarding how prognosis and end-of-life issues can be discussed with minimised negative impact.

PRACTICE IMPLICATIONS

Recognition of factors promoting adjustment, acceptance and readiness and use of the communication skills and therapeutic relationship elements identified may assist in optimising discussions and help patients plan care, achieve more control of their situation and enjoy an optimal quality-of-life.

Screening for motor deficits using the Pediatric Evaluation of Disability Inventory (PEDI) in children with language impairment

OBJECTIVE

To evaluate the association between the Pediatric Evaluation of Disability Inventory (PEDI) motor and self-care domains with the Peabody Developmental Motor Scales-second edition (PDMS-2) gross motor and fine motor sub-scales.

METHODS

Forty children (35-62 months) with primary language impairment (PLI) were recruited. The PEDI was completed at admission and the PDMS-2 was administered within 1 month by an OT, who was unaware of the PEDI results.

RESULTS

Correlation between PEDI mobility and PDMS-2 gross motor domains was r = 0.23 (p = 0.15) and between PEDI self-care and PDMS-2 fine motor domains was r = 0.12 (p = 0.47). Associations between PEDI and PDMS-2 scores for age, gender and severity of language impairment sub-groups were poor-to-moderate.

CONCLUSION

Findings indicate the PEDI is not sufficiently accurate to screen for motor deficits in children with PLI. More sensitive measures of motor performance are needed to detect subtle motor deficits in children with PLI.

The low prevalence of allergic disease in Eastern Europe: are risk factors consistent with the hygiene hypothesis?

BACKGROUND

The prevalence of allergic disease is known to be low in Eastern Europe.

OBJECTIVE

To assess the association of suspected risk factors, including several closely linked to the hygiene hypothesis, with allergic symptoms and atopic sensitization in young school-aged children.

METHODS

Observational study of 13 889 Belarusian children followed up at age 6.5 years in the Promotion of Breastfeeding Intervention Trial (PROBIT). Allergic symptoms and diseases were based on parental responses to the International Study of Asthma and Allergy in Childhood questionnaire, and prick tests to five common inhalant allergens were performed using standard methods.

RESULTS

Significantly increased risks of wheezing and hayfever symptoms in the past 12 months, and of recurrent itchy rash were observed in boys, children with a positive first-degree family atopic history, and those who had received probiotics (especially as prophylaxis with antibiotic use). Pet ownership, contact with farm animals, the presence and number of younger and (especially) older siblings, and residency in rural areas of Western Belarus were associated with reduced risks. Maternal postnatal smoking was associated with wheezing and hayfever symptoms, while the duration of exclusive breastfeeding was not protective against any of the studied outcomes. The risk factors for allergic symptoms were similar in children with positive skin-prick tests to those in the overall cohort.

CONCLUSION

Many of the risk and protective factors we identified are consistent with those reported in Western countries and with the hygiene hypothesis. Further research on dietary and other environmental and genetic factors is necessary to understand the low prevalence of allergic disease in Belarus and other Eastern European countries.

Actual vs. best practices for young children with cerebral palsy: a survey of paediatric occupational therapists and physical therapists in Quebec, Canada

RATIONALE

Cerebral palsy (CP) constitutes a substantial portion of paediatric rehabilitation, yet little is known regarding actual occupational therapy (OT) and physical therapy (PT) practices. This study describes OT and PT practices for young children with CP in Quebec, Canada.

METHODS

This was a cross-sectional survey. All eligible, consenting paediatric occupational therapists (OTs) and physical therapists (PTs) were interviewed using a structured telephone interview based on vignettes of two typical children with CP at two age points--18 months and 4 years. Reported practices were grouped according to the International Classification of Functioning, Disability and Health (ICF).

RESULTS

91.9% of PTs (n=62; 83.8% participation rate) and 67.1% of OTs (n=85; 91.4% participation rate) reported using at least one standardized paediatric assessment. OT and PT interventions focused primarily on impairments and primary function (such as gait function and activities of daily living). Both professions gave little attention to interventions related to play and recreation/leisure. Clinicians reported the need for more training and education specific to CP and to the use of research findings in clinical practice.

CONCLUSION

Wide variations and gaps were identified in clinicians' responses suggesting the need for a basic standard of OT and PT management as well as strategies to encourage knowledge dissemination regarding current best practice.

The expression of stem cell factor and c-kit receptor in human asthmatic airways

BACKGROUND

Asthmatic airways are characterized by infiltration with a variety of inflammatory cells such as mast cells and eosinophils. Stem cell factor (SCF) is an important activating and chemotactic factor for both mast cells and eosinophils. In addition, it is a critical growth and differentiation factor for mast cells.

OBJECTIVES

To investigate the contribution of SCF to the pathogenesis of asthma, we examined the expression of SCF and its receptor c-kit in bronchial biopsies and bronchoalveolar lavage (BAL) specimens obtained from asthmatic subjects (n=13) and non-asthmatic control subjects (n=10).

METHODS

SCF and c-kit were detected by in situ hybridization (ISH) and immunocytochemistry (ICC). In order to phenotype the cells expressing SCF and c-kit in asthmatic tissue and BAL cells, combined ISH and ICC were also performed.

RESULTS

There was a significant difference (P<0.001) in the SCF mRNA expression in asthmatic airway epithelium (70.38+/-12.33% positive cells) compared with controls (12.7+/-17.21% positive cells). There was also a significant difference in subepithelial SCF-mRNA expression, being higher in asthmatics (P<0.001). A significant difference was also found in c-kit receptor mRNA expression in asthmatic biopsies both in epithelium (P<0.001) and subepithelium (P<0.05) compared with controls. ICC results were consistent with the ISH for both SCF and c-kit receptor from asthmatics and controls. The SCF and c-kit receptor mRNA and immunoreactivity in cells recovered from bronchial washing were also significantly higher in asthmatics compared with controls (P<0.05). While SCF expression was localized predominantly in the epithelial layer in bronchial biopsy tissues, alveolar macrophages were found to be the major source of SCF in bronchial washing from asthmatic subjects.

CONCLUSION

The results of this study demonstrate the increased expression of SCF and its receptor, c-kit within human asthmatic airways, which suggests an important role of this cytokine in the pathophysiology of asthma.

Inhibition of IgE production in vitro by intact and fragmented intravenous immunoglobulin

BACKGROUND

Intravenous immunoglobulin (IVIG) has been shown to suppress Ig production both in vivo and in vitro. We have previously found that IVIG inhibits IgE synthesis in human tonsillar B cells stimulated with IL-4 and anti-CD40 antibody.

OBJECTIVE

The purpose of this study was to further clarify the mechanism behind the inhibition of IgE production by IVIG through comparing the effects of intact whole molecular IVIG and the F(ab')(2) or Fc fragments of IVIG.

METHODS

Human B lymphocytes were purified from tonsils. Cell proliferation was measured by means of tritiated thymidine incorporation. IgE was determined by means of ELISA. Cell-cycle analysis was performed by using flow cytometry.

RESULTS

Both intact and fractionated IVIG inhibited anti-CD40- and IL-4--stimulated IgE production in a dose-dependent manner. The maximal inhibition was achieved at 67 micromol/L (eg, 10, 6, and 4 mg/mL for intact IVIG, F[ab'](2), and Fc, respectively). The effect of F(ab')(2) was more pronounced than that of Fc at equimolar concentrations. Similarly, both intact and fragmented IVIG dose-dependently decreased tritiated thymidine incorporation. F(ab')(2) was also more potent than Fc in this effect. Heat-aggregated IVIG exhibited similar potency to regular IVIG in inhibiting B-cell proliferation. The inhibitory effects of IVIG were unlikely to have been caused by the induction of apoptosis because neither intact nor fractionated IVIG had a significant effect on cell-cycle parameters at the concentrations used.

CONCLUSION

These data suggest that both F(ab')(2) and Fc portions contribute to the inhibition of in vitro IgE production by IVIG. The role of the F(ab')(2) portion is more important than that of the Fc portion.

IL-16 inhibits IL-5 production by antigen-stimulated T cells in atopic subjects

BACKGROUND

We have previously shown increased expression of the CD4+ cell chemoattractant IL-16 at sites of airway allergic inflammation. Little is known about the significance of IL-16 in allergic inflammation and its role in allergen-driven T-cell cytokine responses. Because IL-16 interacts specifically with CD4+ T cells, we hypothesized that IL-16 released at sites of inflammation may modulate the pattern of cytokines produced by CD4+ T cells.

OBJECTIVE

We investigated the effects of exogenous rhIL-16 on cytokine production of PBMCs from atopic and nonatopic subjects in response to antigen and PHA.

METHODS

Primary cultures of freshly isolated PBMCs from ragweed-sensitive atopic subjects and nonatopic subjects were stimulated with ragweed or PHA in the presence or absence of rhIL-16. Supernatant levels of IL-4, IL-5, and IFN-gamma were determined by means of ELISA at different time points between 2 and 6 days. Effects of IL-16 on antigen-induced cellular proliferative responses were determined.

RESULTS

No IL-4 protein was detected after antigen stimulation of PBMCs from atopic subjects, whereas significant levels of IL-5 were measured on day 6 (median, 534.9 pg/mL). IL-5 secretion was abolished in PBMC cultures depleted of CD4+ cells. The addition of rhIL-16 in antigen-stimulated PBMC cultures significantly reduced the amount of IL-5 released (median, 99.8 pg/mL; P <.001). Detectable levels of IFN-gamma (median, 53.3 pg/mL) were identified after antigen stimulation. The addition of rhIL-16 in antigen-stimulated PBMC cultures significantly increased IFN-gamma levels (median, 255.6 pg/mL; P <.05). Effects of rhIL-16 appear to be specific for antigen-stimulated PBMCs in atopic subjects because rhIL-16 did not alter IL-5 or IFN-gamma production in response to PHA nor did rhIL-16 alter cytokine production in nonatopic normal subjects.

CONCLUSION

These studies suggest that IL-16 can play a role in regulating the production of cytokines seen in allergic states in response to antigen.

Dyskeratosis congenita: an autosomal recessive variant

We describe a woman with dyskeratosis congenita (DKC), microcephaly, and a purple discoloration of the tongue. The latter findings are not commonly described in males with DKC, have been reported in another female patient with this condition, and may represent the phenotype of an autosomal recessive entity of DKC. Results of X chromosome inactivation studies did not support X-linked DKC in our family. The additional findings of an affected brother and parental consanguinity support the hypothesis of autosomal recessive inheritance.

Characterization of B lymphocytes rescued from apoptosis by platelet-activating factor

B lymphocyte development is characterized by deletion via apoptosis of immature cells that are insufficiently stimulated. We have previously demonstrated that crosslinking of the B cell receptor (BCR) using anti-IgM antibodies (alphaIgM) (2 microg/ml) in Ramos B lymphoblastoid cells causes deletion of 30-40% of cells by apoptosis in 24 h. Addition of the potent lipid mediator platelet-activating factor (10(-7) M) to alphaIgM stimulated Ramos cells significantly decreases the number of apoptotic cells as measured by annexin V labeling. We have characterized the phenotype of Ramos cells that have not become apoptotic following BCR stimulation. In these cells, there is a significant decrease in the surface expression of the VLA-4 adhesion molecule (31% of control expression) and surface IgM expression (sIgM) (53% of control expression). Significantly fewer cells co-incubated with platelet-activating factor (PAF) underwent apoptosis, and the remaining cells maintained control levels of VLA-4 (104% of control expression) and sIgM expression (104% of control). All of these protective effects were inhibited by the specific PAF receptor antagonist, WEB 2170. The action of PAF on alphaIgM induced apoptosis was not inhibited by either cycloheximide or cytochalasin B, suggesting that de novo protein synthesis and F-actin polymerization were not implicated in the rescue of Ramos cells by PAF. In contrast, the ability of PAF to maintain sIgM and VLA-4 expression at control levels was inhibited by cycloheximide (7. 5 microg/ml). Cytochalasin B (5 microg/ml) had no effect on sIgM expression but blocked the decrease in VLA-4 expression mediated by alphaIgM. These data indicate that PAF's effect on rescuing and maintaining alphaIgM stimulated Ramos B cells is mediated via at least two pathways. Abrogation of apoptosis does not require de novo protein synthesis, while maintenance of sIgM and VLA-4 expression requires protein synthesis.

Intravenous immunoglobulin inhibits IgE production in human B lymphocytes

BACKGROUND

Intravenous immunoglobulin (IVIG) is commonly used as both an immune-enhancing and immune-modulating agent. Treatment with high doses of IVIG diminishes IgE secretion in patients with severe steroid-dependent asthma.

OBJECTIVE

We studied the action of IVIG on IgE production in highly purified B lymphocytes stimulated without additional T cells to determine the action of IVIG on B lymphocytes.

METHODS

Human B cells were purified from tonsils, and T lymphocytes were removed by E-rosetting. B cells were cultured with IL-4 (400 U/mL) and anti-CD40 antibodies (1 microg/mL¿, with or without additional IVIG. Cell proliferation was determined by 3[H]-thymidine uptake, and supernatant IgE was determined by ELISA. Cell cycle analysis was performed by flow cytometry, and IgE transcripts were measured by in situ hybridization.

RESULTS

IVIG (5 mg/mL) decreased B-cell proliferation in IL4/anti-CD40-stimulated B cells by an average of 74% (+/-6%). Addition of IVIG up to 48 hours after initiation of cell culture led to significant diminution of cell proliferation at 96 to 120 hours. This effect was dose dependent, with 10 mg/mL being the most effective and doses under 0.1 mg/mL having minimal effect. IVIG diminished the number of stimulated cells progressing in the cell cycle by 30%, and there was no difference in cell viability between IVIG-treated and IVIG-untreated cells. The production of IgE in culture by anti-CD40/IL4-stimulated B lymphocytes was curtailed by greater than 80% after addition of 5 mg/mL IVIG. This was associated with a decrease in IgE (epsilon) transcripts in IVIG-treated cultures.

CONCLUSION

These data indicate that diminution of IgE production in anti-CD40/IL-4-stimulated B cells by IVIG is due to inhibition of early events related to proliferation and progression in the cell cycle.

Phenotypic features of selective T cell deficiency characterized by absence of CD8+ T lymphocytes and undetectable mRNA for ZAP-70 kinase

Selective T cell deficiency is a rare immune deficiency characterized by the absence of CD8+ T lymphocytes and depressed/absent T cell function. This syndrome has been associated with mutations in the gene for ZAP-70, a tyrosine kinase that has profound effects on signaling via the T cell receptor. In this paper we describe a patient with selective T cell deficiency and certain phenotypic features that are unique among the small number of patients described. The patient had virtually absent T cell function, hypogammaglobulinemia, and no response to vaccination. The T lymphocytes failed to respond to mitogenic stimuli, even in the presence of exogenous interleukin 2. Similar to other patients with this disorder, the T cells were capable of proliferating when stimulated by pharmacologic agents such as phorbol ester and ionomycin. While peripheral blood T cells had limited capability to increase cytosolic Ca2+ levels in response to mitogenic stimulation, thymocytes responded to a large panel of antibodies and mitogens. This report broadens the spectrum of clinical presentations associated with selective T cell deficiency and, for the first time, compares the responses of both peripheral T cells and thymocytes. The data support the concept that the defect in signal transduction resulting from the absence of ZAP-70 is primarily manifested following export of T lymphocytes from the thymus and that selection of CDS-positive T cells is dependent on the presence of ZAP-70.

Specific antibody responses to diphtheria/tetanus revaccination in children evaluated for immunodeficiency

BACKGROUND

Assaying specific antibody levels against well-defined antigens such as diphtheria (D), tetanus (T), and more recently Haemophilus is used as one indicator of humoral immune reactivity when evaluating patients for immunodeficiency. The nature of the response to booster vaccine in this group of patients is not well defined.

OBJECTIVE

To define the response to D/T booster vaccination in patients with nonprotective antibody levels in order to distinguish immunocompetent from immunodeficient children.

METHODS

Patients between the ages of 16 months and 17 years referred for possible immunodeficiency were assessed for specific antibody levels as part of a standard immunologic evaluation. Twenty-six previously immunized patients had antibody titers less than or equal to 0.2 IU against D and/or T or another abnormal vaccine response. All of these patients received boosters of diphtheria and tetanus vaccine (D2T5). Diphtheria and tetanus antibody levels were assayed 4 weeks following booster vaccination.

RESULTS

Of the twenty-six subjects, a subset of patients (6) failed to show significant elevations in specific-serum antibody titers to diphtheria and/or tetanus and were thus labeled nonresponders. These patients were retrospectively compared with their responder counterparts examining specific antibody titers pre-immunization and post-immunization, serum immunoglobulins, and clinical presentation. The groups showed no significant difference in baseline specific antibody measures but following re-immunization responders showed a 31.34-fold and 22.33-fold increase in D and T antibody levels, respectively. In contrast, nonresponders produced only a 2.62-fold to D and 6.15-fold increase to T (all group comparisons P < .05). Clinical presentation also tended to be more severe in the nonresponder group.

CONCLUSIONS

These data stress the importance of specific antibody titers pre-immunization and post-immunization in the assessment of immunodeficiency states, and emphasize the different characteristics of responses between diphtheria and tetanus toxoids. The ability to achieve the minimum protective antibody level does not necessarily denote immune competence. Serum immunoglobulin levels and baseline antibody titers are insufficient for the functional assessment of the immune response. The ability to generate antibody responses following booster vaccination is a more complete measure of overall immune competence and should be considered when evaluating patients for replacement immunoglobulin therapy.

Platelet-activating factor abrogates apoptosis induced by cross-linking of the surface IgM receptor in a human B lymphoblastoid cell line

B lymphocyte development is characterized by deletion, via apoptosis, of immature cells that are stimulated via the B cell receptor in the absence of a second signal. We have investigated whether platelet-activating factor (PAF), a potent B lymphocyte activator, can provide a complementary signal with B cell receptor ligation to abrogate apoptosis. Cross-linking of the surface IgM on Ramos B lymphoblastoid cells using anti-IgM Abs (2 microg/ml) caused programmed cell death in 34 +/- 5.4% of the cells. Coincubation of PAF (10(-7)M) with alphaIgM led to a significant decrease in apoptotic cells as measured by DNA laddering and TUNEL assay (13.8 +/- 3%). The effect of PAF was dose dependent (10(-7)-10(-9) M) and was inhibited by the specific PAF receptor antagonist, WEB 2170. PAF protected cells from the effect of alphaIgM for up to 1 h after it was added. alphaIgM-induced programmed cell death in Ramos cells was blocked by catalase and, therefore, is caused in part by the production of toxic hydroxyl radicals from hydrogen peroxide. We investigated the action of PAF on markers of intracellular oxidation. H2O2 in low doses induced apoptosis, via production of OH. radicals. PAF inhibited H2O2-induced apoptosis in Ramos cells; it also attenuated H2O2- and alphaIgM-mediated increases in hydroxyl radical (OH.) as measured by the oxidation of 2',7'-dichlorofluorescein diacetate to 2',7'-dichlorofluorescein and blocked the depletion of reduced glutathione induced by alphaIgM. PAF maintained IgM secretion, which was greatly inhibited by incubation with alphaIgM alone. These data indicate that PAF potentially provides an important cosignal to surface IgM-stimulated Ramos cells by inhibiting apoptosis. This is in part due to the activity of PAF in the oxidant/ antioxidant pathway.

Platelet-activating factor abrogates apoptosis induced by cross-linking of the surface IgM receptor in a human B lymphoblastoid cell line

B lymphocyte development is characterized by deletion, via apoptosis, of immature cells that are stimulated via the B cell receptor in the absence of a second signal. We have investigated whether platelet-activating factor (PAF), a potent B lymphocyte activator, can provide a complementary signal with B cell receptor ligation to abrogate apoptosis. Cross-linking of the surface IgM on Ramos B lymphoblastoid cells using anti-IgM Abs (2 microg/ml) caused programmed cell death in 34 +/- 5.4% of the cells. Coincubation of PAF (10(-7)M) with alphaIgM led to a significant decrease in apoptotic cells as measured by DNA laddering and TUNEL assay (13.8 +/- 3%). The effect of PAF was dose dependent (10(-7)-10(-9) M) and was inhibited by the specific PAF receptor antagonist, WEB 2170. PAF protected cells from the effect of alphaIgM for up to 1 h after it was added. alphaIgM-induced programmed cell death in Ramos cells was blocked by catalase and, therefore, is caused in part by the production of toxic hydroxyl radicals from hydrogen peroxide. We investigated the action of PAF on markers of intracellular oxidation. H2O2 in low doses induced apoptosis, via production of OH. radicals. PAF inhibited H2O2-induced apoptosis in Ramos cells; it also attenuated H2O2- and alphaIgM-mediated increases in hydroxyl radical (OH.) as measured by the oxidation of 2',7'-dichlorofluorescein diacetate to 2',7'-dichlorofluorescein and blocked the depletion of reduced glutathione induced by alphaIgM. PAF maintained IgM secretion, which was greatly inhibited by incubation with alphaIgM alone. These data indicate that PAF potentially provides an important cosignal to surface IgM-stimulated Ramos cells by inhibiting apoptosis. This is in part due to the activity of PAF in the oxidant/ antioxidant pathway.

Possible new variant of Nijmegen breakage syndrome

We report on a child with microcephaly, small facial and body size, and immune deficiency. The phenotype is consistent with Nijmegen breakage syndrome (NBS), with additional clinical manifestations and laboratory findings not reported heretofore. Most investigations, including the results of radiation-resistant DNA synthesis, concurred with the diagnosis of NBS. Cytogenetic analysis documented abnormalities in virtually all cells examined. Along with the high frequency of breaks and rearrangements of chromosomes 7 and 14, we found breakage and monosomies involving numerous other chromosomes. Because of some variation in the clinical presentation and some unusual cytogenetic findings, we suggest that our patient may represent a new variant of Nijmegen breakage syndrome.

Intravenous immune globulin: an alternative therapy in steroid-dependent allergic diseases

A fundamental feature of asthma is abnormal airway function, now recognized to result from both acute and chronic inflammatory changes. Central to the development of these inflammatory changes may be the activation of T cells and the release of pro-inflammatory cytokines. In the skin, a similar cascade of events may underlie the pathogenesis of atopic dermatitis. Asthma and atopic dermatitis often share several features that may be important in their pathogenesis: T-cell infiltration of the tissues, elevated IgE levels, and a history of known triggers associated with positive immediate skin-test reactions. In both diseases, administration of intravenous immune globulin (IVIG) on a regular basis appears to reduce the need for systemic corticosteroids, reduce symptoms and for asthmatics, reduce hospitalization costs. Although the mechanism of action of IVIG in these disorders remains to be defined, it may be exhibiting significant anti-inflammatory activity. IVIG may be a potent alternative in the treatment of severe, steroid-dependent allergic disorders, reducing steroid dependency.

Immunotherapy for childhood asthma: is there a rationale for its use?

OBJECTIVE

This paper reviews the literature regarding immunotherapy in the management of childhood asthma. Immunotherapy is a well established treatment of venom allergy and allergic rhinitis, however its use in asthma remains controversial.

DATA SOURCES

We reviewed the pediatric literature from 1966 to 1994 and evaluated the existing studies for clinical efficacy of immunotherapy in childhood asthma.

STUDY SELECTION

Only 12 purely pediatric studies existed over the time period that we reviewed. The studies used a variety of different antigens including house dust, house dust mite, grass, mold, cat, dog, and combinations of antigens.

RESULTS

In reviewing the studies, we assessed study duration, number of subjects, whether it was blinded, placebo controlled or open labeled, the measures of clinical efficacy and the assessments of specific and nonspecific bronchial reactivity. The studies were very heterogeneous, and therefore direct comparison and extrapolation of conclusions was difficult. The majority of the studies demonstrated either an improvement in asthmatic symptoms or a decrease in bronchial reactivity to the specific antigen employed, or both. The minority of studies demonstrated no clinical efficacy. The most consistent evidence of benefit was suggested in those trials employing house dust mite therapy, while immunotherapy for grass and cats demonstrated some benefit but the number of studies employing these treatments was very small. There are no trials that provide convincing evidence that immunotherapy with dog and mold antigens is effective for childhood reactive airway disease.

CONCLUSION

Asthma is a multifactorial disease with many triggers. In establishing a role for immunotherapy one must consider all the different aspects such as allergic triggers, environmental stresses, and viral infections. The literature is unclear as to when immunotherapy should be initiated for childhood asthma. While there are suggestions that immunotherapy should be considered for the child with mild or moderate asthma and dust mite sensitivity when pharmacotherapy is not efficacious, the immunomodulatory properties of immunotherapy may actually be more tailored for early intervention in asthma rather than for use once symptoms have occurred. More research is required in order to clarify whether immunotherapy should be recommended more often for the treatment of childhood asthma.

The L-selectin antibody FMC46 mediates rapid, transient increase in intracellular calcium in human peripheral blood mononuclear cells and Daudi lymphoma cells

We report the induction of intracellular calcium mobilization [Ca2+]i in normal peripheral blood mononuclear cells (PBMC) and Daudi cells following binding with the L-selectin monoclonal antibody FMC46. The [Ca2+]i signal was mediated directly by binding of FMC46 without cross-linking antibodies. Increased [Ca2+]i was not induced by other L-selectin antibodies tested (TQ1, Leu8, Lam1.3). The increase in [Ca2+]i was rapid and was blocked completely by BAPTA, an agent which chelates intracellular calcium. The increase in [Ca2+]i was observed in calcium-containing as well as calcium free medium, suggesting that FMC46 caused release of Ca2+ from intracellular stores. In both PBMC and Daudi cells, previous signaling via L-selectin still allowed signaling through cross-linking of surface antigen receptor. These data provide evidence for direct alteration of the state of lymphocytes after ligation of a specific L-selectin epitope. L-selectin-mediated signaling does not desensitize signaling through the antigen-receptor and could therefore play a role in preactivating lymphocytes during endothelial transmigration into lymphoid tissues.

Platelet activating factor activates MAPK and increases in intracellular calcium via independent pathways in B lymphocytes

Platelet activating factor (PAF)-stimulation of human B-lymphoblastoid cells results in the activation of microtubule associated protein 2-kinase (MAPK) and increases in intracellular calcium. Although increases in intracellular calcium induce MAPK activation in these cells, PAF can stimulate MAPK activation in the absence of detectable changes in intracellular calcium concentrations ([Ca2+]i). Treatment of the LA350 B-lymphoblastoid cell line with either pertussis toxin (PT) or cholera toxin (CT) blocked PAF-induced changes in [Ca2+]i. However, only PT blocked PAF-induced activation of MAPK as determined by shifts in the mobility of MAPK on immunoblots. In support of this finding, only PT but not CT blocked PAF-induced phosphorylation and activation of p90rsk, an event thought to be distal to MAPK activation. These results suggest that the PAF receptor is mediating MAPK activation through pathways separate from those mediating increases in intracellular calcium.

Activation of MAP2-kinase in B lymphocytes by calcium ionophores

The role of increases in intracellular calcium levels on tyrosine phosphorylation in human B lymphocytes was studied. Stimulation of normal, resting B lymphocytes or B lymphoblastoid cells with the calcium ionophores ionomycin or A23187 induced the tyrosine phosphorylation and the enzymatic activation of microtubule-associated protein-2 kinase (MAP2-K). Treatment of these cells with PMA induced tyrosine phosphorylation of a protein with the identical mobility, as well as the enzymatic activation of MAP2-K. Stimulation of these cells with ionomycin also resulted in increased ribosomal S6 kinase activity. Activation of MAP2-K in B lymphocytes by calcium ionophore was rapid (detectable within 1 min), transient (returning to background levels by 45 min), and dependent on extracellular calcium. These results demonstrate that transmembrane calcium flux induced by calcium ionophore results in the tyrosine phosphorylation and enzymatic activation of MAP2-K in human B cells.